1. Field of the Invention
The invention belongs to the field of aeronautics. The invention can be applied more particularly in the field of military aircraft. The invention can also be applied in the field of civilian aircraft. An object of the invention is a door capable of blocking an opening or aperture made in a fuselage of an aircraft. More specifically, an object of the invention is a door that can have at least two different stable configurations in a closed position. An object of the invention is also an aircraft having at least one such door.
It is an aim of the invention to provide a door which enables, for example, passengers and/or crew to be evacuated when the door is open, and which, as needed, can provide, for example, an observation station that projects out on the fuselage or on the contrary, a smooth surface with no aerodynamic drag. It is an additional aim of the invention to facilitate interchangeability between possible functions of the door in addition to the blocking function.
2. Description of the Prior Art
An aircraft is generally formed by a fuselage and a wing structure fixedly joined to the fuselage. The fuselage, or body of the aircraft, comprises at least one door, or hatch, enabling communication between the exterior and the interior of the fuselage.
A known example of a door is a door provided with a frame fixedly joined to the fuselage and a flap capable of being hinged on the frame. In an open position, the flap is at a distance from the frame and thus releases an access to the fuselage. In a closed position, the flap is applied to the frame so as to block access to the fuselage. The flap has a smooth external surface, optimizing the aerodynamic profile of the fuselage and preventing aerodynamic drag. The term “external surface of the flap” is understood to mean the face of the flap that is directed to the exterior of the aircraft.
Generally, a door of this kind serves as a usual communications door, namely a door used for the boarding of passengers and/or crew, or as an emergency door used in the case of emergency evacuation. The door may be provided with a port. The port gives a passenger limited observation of what is happening outside the aircraft. Indeed, the field of observation through the port does not cover a view of what is happening at the sides or towards the top and/or the bottom of the aircraft.
There are known ways, especially in the field of military aircraft, for providing the fuselage with an observation station by which the surroundings of the aircraft can be seen over 360°, as well as upwards. For example, an external wall of the fuselage is provided with a dome made out of a transparent material. The dome is located, for example, on another front part of the fuselage, and covers an aperture in the wall of the fuselage. A person, from inside the fuselage, may penetrate an inner wall of the dome and observe the exterior. The term “internal volume of the dome” is understood to mean the volume made between the wall of the dome and the wall of the fuselage, the dome forming a projection on said wall. Such a dome is mounted so as to be fixed to the fuselage. Since the dome forms a projection on the fuselage, it increases the surface area of the aircraft on with the tearing forces can be exerted when the aircraft is in flight. An aerodynamic drag is created at the position of the aerodynamic dome, diminishing the kinetic performance of the aircraft as well as the stability of said aircraft.
This observation dome may furthermore be disadvantageous in a military aircraft under enemy fire. Since the dome forms a projection on the fuselage, it is a visible and easy target for enemy fire. Furthermore, the material used is generally light so as not to excessively increase the total weight of the aircraft. This material is often flimsier than the materials used to manufacture the aircraft itself, i.e. the fuselage, the wing structure, the faring, etc. An impact, for example a bullet impact, in the dome may irreparably damage the aircraft, by allowing depressurization of the interior of said aircraft through a hole formed by the bullet in the dome.
Furthermore, the dome cannot be placed anywhere on the fuselage. Indeed, its space requirement has to be taken into account. In particular, it must be positioned at a sufficient distance from the aircraft doors. The term “sufficient distance” is understood to mean a distance enabling door travel in such a way that the door can be opened and closed without being hampered by the dome.
Furthermore, at present, the external wall of the fuselage of military aircraft is increasingly being fitted with specific devices, such as cameras, weapons, GPS devices or the like which can be controlled from inside the fuselage. The devices increase the general amount of space taken up on the wall of the fuselage. The distribution of the devices then depends on the remaining unoccupied surface on the external wall of the fuselage, and especially on the number of doors and their locations.
In the invention, it is sought to resolve the above-stated problems by proposing a door that is capable, firstly, of blocking a passage between the inside and the outside of the aircraft and, secondly, owing to its particular structure, of fulfilling one or more other functions.
To this end, the door of the invention is mounted rotationally about two independent axes of rotation. A first axis of rotation is situated at the position of a link between hinges of the door and the fuselage. The hinges are fixedly joined to the fuselage and the door, and thus join the door to the fuselage. The first axis of rotation permits door travel so that said door can pass from an open position to a closed position, or vice versa, as needed. A second axis of rotation is located at the position of a link between the hinges of the door and the door itself. Thus, the door may rotate about hinges so that different faces can be applied in turn against the wall of the fuselage.
The door may have means to lock the rotation of the door about the hinges. Thus, the rotation of the door about the second axis is not allowed when said door is in the desired configuration.
Each face of the door may be provided with a particular set of equipment such as an observation dome, a camera, a smooth plate, etc. According to need, a user exposes one face rather than another to the exterior of the aircraft.